A fluid pressure cylinder includes a cylindrical cylinder tube, a piston that is inserted into the cylinder tube in a freely slidable manner, a piston rod that is linked to the piston, and a cylinder head that is fitted to an open end of the cylinder tube and supports the piston rod in a slidable and rotatable manner.
The fluid pressure cylinder further includes a lower clevis that is linked to a base portion of the cylinder tube, and an upper clevis that is linked to an end portion of the piston rod on the opposite side of the piston. The fluid pressure cylinder is linked to an equipment via the lower clevis and the upper clevis.
JP2007-71363A discloses a fluid pressure cylinder having a built-in magnetostrictive displacement sensor that detects relative displacement between a piston rod and a cylinder tube. The magnetostrictive displacement sensor consists of a sensor body, a sensor rod that is provided so as to extend from the sensor body, and an annular magnet disposed on an outer circumference of the sensor rod.
The sensor body is disposed on the outer side of the base portion of the cylinder tube. One end of the sensor rod is inserted into a hollow portion formed in the piston rod, and other end thereof is linked to the sensor body via a hole formed in the base portion of the cylinder tube. The magnet having the annular shape is disposed in the hollow portion of the piston rod so as to face against the outer circumference of the sensor rod.